APPARATUS AND METHOD FOR REDUCING HARMONICS

摘要

The present invention provides systems and methods for reducing harmonics, for example when using an AC to AC converter to drive a load such as a motor drive. In a first embodiment, a plurality of load driving circuits is provided, each drawing current from a 3-phase AC supply and driving an AC load, wherein each of said load driving circuit includes a 3-phase rectifier, with the rectifiers of the load driving circuits being controlled such that the rectification of the AC supply by the load driving circuits is staggered. In a second embodiment, a load driving circuit comprises an electronic inductor configured to control the DC link voltage and/or current such that the current drawn from the AC supply by the load driving circuit has a stepped profile. The first and second embodiments may be combined.

主权项

1. A load driving circuit comprising:
a 3-phase rectifier having an input coupled to a 3-phase AC supply; a DC link stage; an inverter having an input coupled to an output of the DC link stage and an output coupled to a load, wherein the inverter converts an output voltage of the DC link stage into a signal for driving the load; and an electronic inductor configured to control the output voltage and/or output current of the DC link stage such that the current drawn from the AC supply by the load driving circuit has a stepped profile.